import { type UnionToIntersection } from "https://deno.land/x/actionify@0.3.0/src/deps/types.ts";
Convert a union type to an intersection type using distributive conditional types.
Inspired by this Stack Overflow answer.
Examples
Example 1
Example 1
import type {UnionToIntersection} from 'type-fest';
type Union = {the(): void} | {great(arg: string): void} | {escape: boolean};
type Intersection = UnionToIntersection<Union>;
//=> {the(): void; great(arg: string): void; escape: boolean};
A more applicable example which could make its way into your library code follows.
Example 2
Example 2
import type {UnionToIntersection} from 'type-fest';
class CommandOne {
commands: {
a1: () => undefined,
b1: () => undefined,
}
}
class CommandTwo {
commands: {
a2: (argA: string) => undefined,
b2: (argB: string) => undefined,
}
}
const union = [new CommandOne(), new CommandTwo()].map(instance => instance.commands);
type Union = typeof union;
//=> {a1(): void; b1(): void} | {a2(argA: string): void; b2(argB: string): void}
type Intersection = UnionToIntersection<Union>;
//=> {a1(): void; b1(): void; a2(argA: string): void; b2(argB: string): void}